The present invention relates generally to oil systems for internal combustion engines, and more specifically, to an oiling system for a two-stroke engine in an outboard motor having an oil reservoir remote from the oil system vent.
Typically, two-stroke outboard marine engines do not have a separate oiling system. That is, these prior art engines require pre-mixing lubricant and fuel so that the lubricant dissolves in the fuel to lubricate the engine. This requires consistent, accurate measuring and agitation of the mixture. There are many disadvantages to the prior art system of pre-mixing lubricant and fuel. For example, since various two-stroke engines require different mix concentrations, many outboard marine engine owners also own other two-stroke engine equipment, such as various lawn and garden equipment and ATV""s, they may store several different concentrations of oil/fuel mixture. This is not only an aggravation to the owner, but is also problematic if the containers become mixed up and the owner uses the wrong concentration for a particular two-stroke engine. While this is not catastrophic, if run over time with the wrong concentration, a two-stroke engine can wear excessively.
The present invention is for use in a unique lubrication system for two-stroke engines. Such a lubrication system must provide lubrication to each cylinder of the engine and provide lubrication to the fuel system to properly lubricate the fuel metering and injection system from an oil reservoir.
It is desirable in such systems to place the oil reservoir in the bilge section of the boat. However, since such prior art oil reservoirs have a vent located directly on the oil reservoir, and often in the cap on the top of the reservoir, water in the bilge section of the boat can be ingested into the tank through the vent. That is, as oil in the tank is consumed, the volume must be displaced, and is usually displaced with air from the vent. While occasionally the oil reservoir may become submerged in water and the water can be directly ingested into the oil reservoir by the vacuum created by the oil consumed, water may also be consumed if the oil reservoir is not completely submerged, but only subjected to the normal use of the boat in which water splashes on the oil reservoir thereby allowing ingestion of air and water. Since water will sink to the bottom of the tank and the oil will float on top of the water due to their relative densities, and since oil is often drawn from the bottom of the tank to maximize volume of the tank, the oiling system can draw water in place of oil if the water level reaches the oil pickup. Water in place of oil, or water mixed with oil, can severely damage an engine.
It would therefore be desirable to have an oiling system that could accommodate a completely sealed oil reservoir that may be located in the bilge of the boat, and may be susceptible to complete submersion.
The present invention includes a ventless oil reservoir and a remote oil system vent for an outboard motor that solves the aforementioned problems.
In accordance with one aspect of the invention, an oil system vent for an outboard motor includes an oil reservoir having an oil supply outlet and an oil supply return. The oil reservoir is designed to be located below the water line of a boat, and in particular, in the bilge area of the boat. The oil reservoir is free of any internal ventilation means such that the oil reservoir can be completely submerged in water, and as long as the cap is secured tightly, water will not enter the oil reservoir, even when the oil reservoir is under a slight vacuum. The oil system vent includes an oil return port having an oil input and an oil output. The oil input receives pressurized lubricant and the oil output and returns the pressurized lubricant to the oil supply return of the oil reservoir. The oil return port also has a vent port that is in communication with atmospheric pressure when lubricant is drawn and used from the oil reservoir. In this manner, the vent port allows air to displace the used lubricant in the oil reservoir.
In accordance with another aspect of the invention an oil system for a two-stroke engine includes a ventless oil reservoir having a pump associated therewith to draw and pump lubricant therefrom. A closed loop in an oil routing system of the oiling system includes the ventless oil reservoir and pump, and also includes a pressure regulator and a solenoid valve. The solenoid valve is positioned in the closed loop to periodically open the closed loop and divert lubricant to the two-stroke engine. A remotely located vacuum controlled vent valve is located in the closed loop to allow air into the closed loop when the solenoid valve periodically diverts lubricant to the two-stroke engine.
Another aspect of the invention includes a boat and outboard motor combination that includes an outboard motor mounted to the transom of a boat and further includes a ventless oil reservoir located in the boat that does not allow water ingestion even when completely submersed in water. The combination includes an oiling system having a pump to draw lubricant from the ventless oil reservoir and route the lubricant through the oiling system and back to the ventless oil reservoir. The oiling system periodically diverts the lubricant to the engine of the outboard motor. The combination also includes a remote ventilation means for venting the ventless oil reservoir while lubricant is periodically diverted to displace used lubricant with air to avoid excessive vacuum in the oil reservoir.
The invention also includes a method of venting an oil reservoir of an outboard motor that includes providing a ventless oil reservoir and routing lubricant from the ventless oil reservoir through an oil pump, to an oil system, and back to the ventless oil reservoir in a closed loop. The method includes periodically opening the closed loop in the oil system to draw and use lubricant from the ventless oil reservoir. A vent valve is provided at a higher elevation than the ventless oil reservoir. The vent valve automatically opens when lubricant is consumed to displace the consumed lubricant with air within the ventless oil reservoir.
Various other features, objects and advantages of the present invention will be made apparent from the following detailed description and the drawings.